Despite the complex history of the cercopithecoids, Perelman thinks that the family splits into two big sub-families. The Colobinae started diversifying around 12 million years ago, but they’ve given rise to a large number of African and Asian species. Most of them live in trees and eat leaves These include the colobus monkeys (far left), the langurs and leaf monkeys (left), and the aptly-named “odd-nosed monkeys” (including the bizarre proboscis monkey (right) and China’s beautiful golden snub-nosed monkey (far right)).